Synthesis and characterization of fly ash activated zeolites (FAZ) for the removal of sulphate ions from acid mine drainage (AMD)

Sulphate ions removal from Acid mine drainage (AMD) is crucial to mitigate its adverse impact on aquatic and terrestrial ecosystem. Similarly, surplus and unused quantity of the Fly ash, waste from coal-based power plants is also challenging problem. In the present study, Fly ash based low-cost adsorbents (NaOH at 100 oC and HCL at 400 oC) activated Fly ash were synthesized using thermal activation methods. The composition and surface morphology studies were conducted using FTIR, XRD, XRF and SEM-EDX analysis. The Synthesized adsorbents were used to removal of sulphatic ion under various experimental conditions such as initial concentration (5 to 50 mg L-1), contact time (0 to 180 minutes), dose (5 to 40 mg L-1), solution pH (4.5, 5 and 5.5 pH). The optimum removal was 63 +/- 1.4 % and 65 +/- 1.6 % at room temperature 27 degrees C, pH 5.5 and 0.6 g L-1 dose of FAZ-HCl and FAZ-NaOH adsorbents respectively. The kinetics models and adsorption isotherm were determined to be pseudo second order (R2 > 0.9919) for FAZ-HCl and pseudo first order which (R2 > 0.9857) was validated and fitted by Freundlich isotherm (R2 > 0.9806 and 0.9932) for FAZ-HCl and FAZ-NaOH.